1. Technical Field
The present invention relates to a gyro sensor and an electronic apparatus.
2. Related Art
There has been a known gyro device described in JP-A-2006-201011 in the form of an oscillation piece for detecting an angular velocity.
The gyro device described in JP-A-2006-201011 includes a base, first and second detection oscillation arms extending from the base in opposite directions in a Y-axis direction, first and second connection arms extending from the base in opposite directions in an X-axis direction, first and second drive oscillation arms extending from a front end portion of the first connection arm in opposite directions in the Y-axis direction, and third and fourth drive oscillation arms extending from a front end portion of the second connection arm in opposite directions in the Y-axis direction. A drive electrode is formed on each of the first to fourth drive oscillation arms, and a detection electrode is formed on each of the first and second detection oscillation arms.
The thus configured gyro device detects an angular velocity as follows: The first to fourth drive oscillation arms are first allowed to oscillate in such a way that the first, second drive oscillation arms and the third, fourth drive oscillation arms oscillate in a plane-symmetrical manner with respect to a YZ plane. When an angular velocity around a Z axis is applied to the gyro device in this state, a Coriolis force acts on the gyro device, and detectable oscillation in the X-axis direction is induced in the first and second detection oscillation arms. The detection electrodes can then detect distortion of the first and second detection oscillation arms resulting from the oscillation to determine the angular velocity around the Z axis.
The gyro device described in JP-A-2006-201011 is, however, only capable of detecting an angular velocity around the Z axis. That is, no angular velocity around the X axis or the Y axis can be detected. To detect angular velocities produced around the X axis and the Y axis, for example, the gyro device needs to be disposed in a vertical attitude. In this case, the thickness of a sensor device disadvantageously increases. Further, to detect angular velocities around a plurality of axes, a plurality of gyro devices need to be provided. In this case, the size of the apparatus disadvantageously increases.